Internalizing Behavioral Externalities: Benefit Integration in Health Insurance
We show that profit-maximizing firms alter product design in the market for Medicare prescription drug coverage to account for underutilization by consumers. Using plausibly exogenous variation in coverage, we examine prescription drug utilization under two different plan structures. We document that plans that cover all medical expenses spend more on drugs than plans that are only responsible for prescription drug spending, consistent with drug spending offsetting some medical costs. The effect is driven by drugs that are likely to generate substantial offsets. Our supply side model confirms that differential incentives across plans can explain this disparity. Counterfactuals show that the externality created by stand-alone drug plans is $405 million per year. Finally, we explore the extent to which subsidies and information provision can mitigate the externality generated by under-consumption.
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Document Object Identifier (DOI): 10.3386/w21783